Radio-transmission system



' Nov. 11, 1924- i,5l5,33l J. BETHENOD RADIO TRANSMISSION SYSTEM Original Filed Aug. 2 192 vvx W .guvantoz JOSEPH BETHENOD @513 M5 61% ya/w] Patented Nov. ll, 1924.

stares JOSEPH BETHENOD, O1 PARIS, FRANCE.

RADIO-TRANSMISSION SYSTEM.

Application filed August 2,1921, Serial No. 489,305. Renewed March 5, 1924.

To all whom it may concern:

Be it known that I, Josnrn BETHENOD, a citizen of the Republic of France, and resident of Paris, France, have invented certain new and useful Improvements in Radio- Transmission Systems, of which the follow ing is a specification, accompanied by drawings.

The object of the present invention is to effect improvements in radiotelegraphic stations comprising a plurality of high frequency generators, In accordance with the present invention, by means of simple operations performed at will, all these generators may be operated simultaneously at the same frequency, whereby the total generating power of the station is applied to the antenna, or these generators may be independently operated at different frequencies, in order to make possible multiplex transmission.

The principle of the invention consists in that the antenna (usually a horizontal network extended in one direction) is divided into a plurality of sections each of which is supplied with current by a high frequency generator, and provisions are made for modifying, if necessary, the effects of the electromagnetic or electrostatic induction between any two sections.

In this manner, a independent stations will be obtained, making possible multiplex transmission of the n degree. Switches are provided for interconnecting at will all of the 4% stations or only a part of these stations, whereby in case 'n:3, triplex, dupleX (one transmission having double the power of the other), or simplex transmission may be effected, and the total power of the station utilized.

In the drawing, Fig. 1 shows an exem plification of the invention wherein 42:2.

Fig. 2 is a modification where 4%:3.

The high frequency generators 1 and 2 are connected, respectively, with sections 3 and 4 of the antenna and ground connection 5.

To eliminate the mutual electromagnetic and electrostatic induction between 3 and 4, a variable transformer 6 is provided, the windings ofthis transformer being located, respectively, in the circuits 1, 3, 5 and 2, 4, 5.

Calculations and experiences show that, under these conditions there exists always a frequency such that, the induction of one section on the other is zero. If the two simultaneous transmissions are so chosen that the wave-lengths are different, but both are in the neighborhood of the wave length corresponding to the above defined frequency, the desired independence is practically attained. If necessary, a strictly zero mutual section may be obtained for the two working frequencies by various'means, such as the interconnection of the two antenna nets by a resistance. the value of which depends on the mutual electrostatic induc tion between these sections of the network,

etc.

According to the present invention, the total antenna is excited by the-generators 1 and 2 in parallel in response to the closure of switch 7. Obviously, the closure ofthis switch may cause also the cutting in of wellknown devices (condensers, etc.), for in creasing the synchronizing element, or adjusting the generators and aerials to the same frequency.

The circuit arrangement shown in Fig. 2 is for the case where 10:3. Three compensating transformers are shown at 8, 9 and 10. Obviously, with n sections, the number of the transformers should be 'n,(n2 1) B in Fig. 2, all or an arbitrary portion of a generators may be connected in parallel.

Having described my invention What 1 claim is:

1. In a radio telegraphic transmission system, an aerial divided into two separate sections, two separate generators, and a transformer having a winding in each of said sections for compensating for induction be tween said sections.

2. In a radio telegraphic transmission system, an aerial divided into to separate sections, a separate generators, a coil in each of said sections, said coils being coupled together for compensating for the induction between said sections.

3. In a radio telegraphic transmission system, an aerial divided into two separate sections, two separate generators each adapted to gent-rate oscillations of either of two different frequencies, means for connecting the generators together for operation on the same frequency, and a coil in each of said sections, said coils being coupled together for compensating for the induction between said sections.

4. In a radio telegraphic transmission y means of switches, not shown n -1 oscillatlons and trans'tormers havmg windings in said sections for compensating for the induction between any of said sections.

5. In a radio telegraphic transmission system, an aerial divided into a separate sections, a separate generators for supplying am 1) M windings in said sections for compensating for the induction between any of said sections and switching means for connecting a plurality of said generators in parallel.

6. In a radio telegraphic transmission system, an aerial divided into two separate sections, two separate generators, and a transformer having a winding in each of said sections for compensating for induction between said sections and an impedance for directly connecting the antenna sections to gether.

7. In a radio telegraphic transmission oscillations and transformers having system, the combination of an aerial divided into a sections with a generator of oscillations for each section, each of said generators being adapted to generate oscillations of a different frequencies, means for connecting a plurality of generators in parallel, and transformers coupled between said sections for compensating for the induction between said sections.

8. In a radio telegraphic transmission system, an aerial divided into two separate sections, two separate generators, and a transformer having a winding in each of said sections for compensating for induction between said sections, and a resistance for directly connecting the antenna sections togcther.

9. In a radio telegraphic transmission system, the combination of an aerial divided into 1% sections, with a generator of oscillations for each section, each of said generators being adapted to generate oscillations of a different frequencies and means for connecting a plurality of said generators in parallel.

JOSEPH BETHENOD. 

